1. Field of the Invention
The present invention generally relates to a ligand molecule-immobilized polymer, a ligand molecule-immobilized particle, a method of detecting a target substance, and a method of separating a target substance.
2. Description of the Related Art
Particles to which biological molecules such as ligand molecules are immobilized have been widely used as affinity purification reagents or sample test reagents in recent years. These particles are typically excellent in dispersibility and show a high affinity for a target substance, and thus a method of producing such particles having these properties has been sought. In other words, there has been a need for a method of producing particles to which ligand molecules are immobilized having the following characteristics: in the production of the particles, the aggregation of the particles does not excessively occur at the time of the immobilization of the ligand molecules to the particles, and a large amount of the ligand molecules can be efficiently immobilized.
Japanese Patent Application Laid-Open No. S59-135887 discloses a method involving: covering the surfaces of hydrophobic particles with a hydrophilic polymer having a functional group; and immobilizing a ligand molecule to the functional group of the hydrophilic polymer. In the method, the ligand molecule is strongly immobilized to each particle through the functional group by a covalent bond, and, furthermore, the surface of each particle is covered with a hydrophilic group, and hence the aggregation of the particles at the time of the immobilization of the ligand molecule is reduced, and ligand molecule-immobilized particles may be produced in good yield.
In addition, Japanese Patent No. 3086427 discloses a method involving: covering the surfaces of hydrophobic particles with a glycidyl methacrylate polymer; and immobilizing a physiologically active substance to a functional group present on the surface of each particle through a chemical bond. The method allows the production of particles having excellent dispersibility and physiological activity because the surface of each particle is covered with a hydrophilic polymer.
However, neither of the methods described in Japanese Patent Application Laid-Open No. S59-135887 and Japanese Patent No. 3086427 allows the immobilization of a sufficiently large amount of ligand molecules to the surfaces of particles, because the number of functional groups that can be formed on the surfaces of the particles is limited. As a result, the affinity of each particle for a target substance is reduced. In addition, since the immobilization reaction is a heterogeneous chemical reaction, the efficiency with which the ligand molecules are immobilized may be poor, and thus a large amount of ligand molecules may be needed for the reaction.